In various condensor systems of power plants, an aqueous medium is recirculated that eventually picks up unwanted oxygen, the oxygen becoming dissolved in the aqueous medium. The presence of dissolved oxygen in such an aqueous medium has a corrosive effect on the downstream components of the system, such as feedwater heaters and steam generators.
Often, oxygen finds its way into the aqueous medium through leakage into the condensor, while further oxygen finds its way into the system at a later stage in the circulating loop. In the condensor, a hotwell or water reservoir is present. Oxygen which enters the aqueous medium before collection of the aqueous medium in the hotwell is considered as oxygen entering above the water level. Oxygen which is entering the aqueous medium below the liquid level in the hotwell and in the lines up to the circulating pumps downstream from the condensor is considered as oxygen entering below the water level.
In such systems, absorption of oxygen into the aqueous medium may occur due to leakage into the system above the water level or leakage below the water level. In existing systems, the need to repair or replace various components due to air leakage, and oxygen absorption therefrom, will depend upon the quantity of oxygen that is being absorbed at a location either above or below the water level in the condensor. For example, a large air leakage into the condensor above the water level, while being apparent, may in fact only result in a minor amount of dissolved oxygen in the aqueous medium. On the other hand, a small air leakage into the system below the water level may be a primary contributing factor to the amount of dissolved oxygen in the aqueous medium.
It is an object of the present invention to provide a method to determine the magnitude of the absorption of oxygen into the aqueous medium from air leakage above the water level relative to the magnitude of the absorption of oxygen into the aqueous medium from air leakage below the water level of a condensate system of a power plant.